The veteran safeties combined for 21 total tackles, two pass breakups, one tackle for loss, and a forced fumble.
Drew Allar's three touchdown passes silenced the Mountaineers in Morgantown.
Warren's ability to block and catch gives opponents headaches.
The Mountaineers are loaded with veterans on the offensive and defensive lines.
The Nittany Lions will kick off against Binghamton on November 4.
Castro-Fields was released by the Washington Commanders a day before.